This is a randomized clinical trial designed to evaluate the safety/efficacy of two dosing regimens of oral nitazoxanide compared to placebo in the treatment of acute uncomplicated influenza in adults and adolescents. The investigators hypothesize that treatment with Nitazoxanide will reduce the duration of symptoms in patients with confirmed influenza infection. Secondarily, the investigators hypothesize that treatment with nitazoxanide will reduce the complications of influenza, severity of symptoms, time lost from work, time to return to normal daily activities.